Tech buses may be used to navigating the flat roads of Silicon Valley, but apparently this bus driver isn't used to the hills of San Francisco.

A private shuttle bus broke down while blocking the J-Church Muni tracks at the intersection of 21st and Chattanooga streets shortly after 9 a.m., blocking trains from moving through, Muni spokesman Paul Rose said. A tipster sent SFist a photo of the mammoth silver bus with its rear sticking out into the street covering the Muni tracks.

It's unclear which company had hired the Royal Coach bus, or where it was headed. Bystanders and media speculated that the bus was hired by some sort of tech company, but that hadn't been immediately confirmed. Rose did confirm that the bus was part of the city's "Private Shuttle Network," where shuttles pay $3.55 a stop to use the Muni-approved bus stops. The pilot shuttle program began Aug. 1.